Fluid propulsion



Patented May 6, 1913.

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NIKOLA TESLA, OF NEW YURK, N. Y.

FLUID PROPULSION.

Specification of Letters Patent.

Patented'May 6, 1913.

Application led October 21, 1909. Serial No. 523,832.

To all whom. it may concern:

Be it known that I, NIKoLA TEsLA, a citizen of the Uni'hd States, residing at New York, in t-he county andState of New York,

have invented certain new and useful Improvements in Fluid Propulsion, of which the following is a full, clear, and exact description.

In the practical application of mechanical.

power based on the use of a fluid as the vehicle of energy, it has been demonstrated that, in order to attain the highest economy,

. 'the changes in Ivelocity and direction Vof movement of the fluid should be as gradual as possible. In the present forms of such apparatus more or less sudden changes,

shocks and vibrations are-unavoidable. Besides, the employment of the usual devices for imparting energy to a fluid, as pistons,

paddles, vanes and blades, necessarily introduces numerous defects andY limitations and adds to the complication,l cost of'production and maintenanceof the machine.

The object of my present invention is to overcome these deficiencies in a paratus designed for the propulsion of ids and to e ect thereby the transmission and .transformation of mechanical energy through the agency of iuids in a more perfect manner, andby means sim ler'and more economical 'than those hereto ore employed. I accoml' plishthis by causing the .propelled iuid to .versely, if the body be place Vmolecular separation.

move in natural pathsV or stream lines of .least resistance, free from constraint and disj turbance such as occasionedl by vanes orl kindred devices, and to change its velocity and direction of movement by imperceptible degrees, thus avoiding the losses dueto-sudden variations while the fluid isv receiving energy.

It is wel] known that a fluid possesses, among others, two salient properties: adhesion and viscosity. Owing to these a body propelled through such a medium encounters a peculiar impediment known as lateral or skin resistance, which 'is twofold; one arising from the shock of the fluid. against the asperities of the solid substance the other from internal forces o osing As an inevita e consequence, a certain amount of the iuid i's dragged along by the movin body. Conl in a fluid in motion, for the same reasons, it is impelled vised for carrying it out by reference/to the accompanying drawings which illustrate an 'operative andk elicient embodiment of the same. v

Figure 1 is a partial end view, and Fig. 2 is a vertical cross section of a pump or compressor constructed and adapted to be `operated in accordance with my invention.

In these drawings the device illustrated y contains a runner composed ofa plurality of flat rigid disks 1 of a suitable diameter, keyed to a shaft 2, and held in position by a v threaded nut 3, a shoulder t and washers 5,

of the requisite thickness. Each disk has a number of central openings 6the solid por- 'tions between which form vspokes 7, preferably curved,as shown, for the purpose of reducing the loss of energy due to the impact of the fluid. The runner is mounted 1n a two part Yvolute casing 8, having stuin boxes 9, and inlets 10 leading to its centra portion. In addition a graduall Widening and rounding outlet 11 is provi ed, formed with a ange for connection to a pipe as usual. The casing 8 rests upon a base 12,

, shown only in part, and supporting t-he bearings for the shaft'2,wl1ich, bein of ordinary construction, are omitted from An understanding of the principle embodied in this device will be gained from the followin description of its mode, of operation. ower being applied to the shaftand therunner set in rotation in the ldirection of the solid arrow the. fluid by reason of its properties of 'adherence and viscosity, upon entering, through the 'inlets 10 and coming in contact with the disks l is taken hold of by the same andlsubjezted to'two forces, one acting tangent-ially in the direction of rotation, and the other radially outward. The combined effect of these tangential and centrifugal forces 1s to propel e drawings.

the fluid with continuously 'increasing veflocity in a spiral path until it reaches `the outlet 11 from which it is ejected. This spiral movement, free and undisturbed and essentially dependent on the roperties of the fluid, permitting it to adjust itself to natural paths or stream lines and to change its velocity and direction by lnsensible legrees, is characteristic of this method of propulsion and advantageous in its application. lVhile traversing the 'chamber inclosing the runner, the particles of the fluid may complete one or more turns, or but a part of one turn. In any given case their path can be closely calculated and graphically represented, but fairly accurate estimate of turns can be obtained simplyfby determining the number of revolutions required to renew the fluid passing through the chamber and multiplying it by the ratiol between the mean spee of the fluid and that of the disks. I have found that the quantity of fluid propelled in this manner is, other conditions being equal, approximately proportionate to the active surface of the runner and to its effective speed. `For thisreason, the performance of such machines augmente at an exceedingly high rate with the increase of their size and speed of revolution.

The dimensions of the device as a whole, and the spacing of the disks in any given lmachine will be determined by the conditions and requirements of special cases. It may be stated that the intervening distance should be the reater, the larger the diameter of the dis s, the longer the spiral path of the fluid and the greater its viscosity. In general, the spacing should be such that the lentire mass of the fluid, before leaving the runner, is accelerated to a nearl uniform velocity, not much below that of the periphery of the disks under normal working con ditions and almost equal to it when the outlet is closed and the particles move in con-4 centric circles. It may also be pointed out that such a pump can be made without openings and spokes in the runner, as by using one or more solid disks, each in its own casing, in which form the machine will be eminently adapted for sewage, dredging vund the like, when the water 1s charged with foreign bodies and spokes or van especially objectionable.

Another application of this principle which I have discovered to be not onl feasible, but thoroughly practicable and elli,L cient, is the utilization .of machines auch as above described for the compression or rarefaction ofair, or gases in general. In such cases it will be found that most of the general considerations obtaining in the case of liquids, properly interpreted, hold true. When, irres fluid, consi erable' ressures .are desired, staging or compoun ma be resorted to inthe usual way the in 'vi ual runners beward the center.

tive of the character of the ing, preferably, mounted on the same shaft. It should be added that the same end may be attained with one single runner by suitable deflect-ion of the fluid through rotative or stationary passages.

The principles underlying the invention are capable of embodiment also in that field of mechanical engineering which is concerned in the use of fluids as motive agents, for while in some respects the actions in the latter case are directly7 op oste to those met with in the propulsion o guids, the fundamental laws applicable in the two cases are the same. In other words, the o eration above described is reversible, for if Water or air under pressure be admitted to the opening 11 the runner is set in rotation in the direction of the dotted arrow by reason of the peculiar propertiesof the fluid which traveling in a spiral path and with continuously diminishing velocity, reaches the orifices 6 and 10 through which it is discharged.

When apparatus of the general character above described is employed for the transmission of power, however, certain departures from structural similarity between transmitter and receiver may be necessary for securing the best result.` I have, therefore, included that part of my invention which is directly applicable to theuse of fluids as motive agents in a separate appli# cation filed January 17, 1911, Serial No. 603,049. It may be here pointed out, however, as -is evident from the above considerations, that when transmitting power from one shaft to another by such machines, any desired ratio between the speeds of rotation may be obtained the diameters of the or by suitably staging the transmitter, the receiver, or both, But it may be stated that in one respect, at least, -the two machines are essentially different. In the pump, the radial or static pressure, due to centrifugal force, is added.

to the tangential or dynamic, thus increasing the effective head and assisting in the ex- I P sion of the fluid. In the motor, on the contrav the first named pressure, be' oppose to that of supply, reduces the e fective head and velocity of radial flow to- Again, inv the propelled machine a great torque is always eslrabl this calling for an increased number or disks and smaller distance of separation, while in the propelling machine, for numerous economic reasons, the rotary eort should be the smallest and the speed greatest practicable. Man other considerations, which will natura y :l themselves, may affect the design an tion, but the preceding is though tain all necessary information 1n hyispopen selection of rd. galt be understood that the principles of construction and operation above set forth, are capable c? embodiment in machines of the most widely diiferent forms, and adapted for the greatest variety of purposes. In the above, I have sought to describe and explain only the general and typical applications of the principle which I believe I am the first-to realize and turn to useful ac` count.

I do not claim in this application the method herein described of imparting energy to a fluid, having made that discovery the subjectof a copending application Serial No. 735,914..

What I claim is:

l. A inachinefor propelling or imparting energy to fluids comprising in combination a plurality of spaced disks rotatably mounted :uid having plane surfaces, an inclosing casing, ports of inlet at the central portion of said casing and through which the Huid is adapted to be introduced to the axial por` tions of the disks, and ports of outlet at the peripheral portion of the casing through which the Huid, when the machine is driven by power, is adaptedto be expelled, as set forth.

2. A machine for propelling or imparting energy to fiuids, comprising in combination a volute casing provided with ports of nlet and outlet at its central and peripheral portions, respectively, and a runner mounted within the casing and composed of spaced disks with plane surfaces having openings adjacent to the axis of rotation.

3. A rotary pump, comprising in combination a plurality of' spacedl disks Witln plane surfaces mounted on a rotatable shaft and provided with openings adjacent thereto, a volute casing inclosing the said disks, means for admitting a fluid into that portion of the casing which containsthe shaft and an outlet extending tangenti-ally from' the peripheral portion of said casing.

In testimony whereof I aix my signature in the presence of two subscribing witnesses.

IFESILA... lVitnesses M. LAWSON DYER, DRURY W. COOPER. 

